Unincorporated Dallas County, Texas requires a development permit for construction, grading, floodplain work and on-site sewage facilities1. Dallas County cannot enact zoning, but it enforces building, subdivision, septic and floodplain rules outside cities23. Dallas County Health and Human Services handles septic questions for land outside city limits4.
At a glance
- Building permit
- A DUAS development permit is required for construction and other development in unincorporated Dallas County1
- Residential code
- Applies to a new home or an addition of at least 500 square feet outside a city's ETJ5
- Zoning
- Dallas County has no authority to enact zoning2
- Septic permit
- Required through the county process, subject to a narrow state exemption67
- RV / mobile-home placement
- County zoning does not restrict occupancy, but DUAS requires a placement permit before placement89
- Minimum home or lot size
- No county zoning minimum; building, septic, platting and floodplain rules still apply8
- Owner-builder exemption
- We could not confirm one; ask DUAS before relying on an exemption10
- County-road driveway
- A permit is required for a connected driveway or culvert11
Who to call
Building permits
Dallas County Department of Unincorporated Area Services (DUAS)
Development permits for construction, grading, floodplain work and other development in unincorporated Dallas County.
Records Building - 500 Elm Street, Suite 6100, Dallas, TX 75202
Building permits
Dallas County Department of Unincorporated Area Services (DUAS)
Applications for development, residential construction, RV or mobile-home placement, driveways, culverts and utility work.
Records Building - 500 Elm Street, Suite 6100, Dallas, TX 75202
Planning & zoning
Dallas County Planning and Development
Zoning questions and an overview of unincorporated-area regulations.
Records Building - 500 Elm Street, Suite 3100, Dallas, TX 75202
Septic permits
Dallas County Health and Human Services
Septic-tank questions for land outside city limits.
Contact details are copied from each office’s official page and were checked against it on September 28, 2026.
Do you need a building permit in Dallas County, Texas?
Yes, for development in unincorporated Dallas County. DUAS requires a development permit for construction, installation, grading, filling, floodplain work and on-site sewage facilities1. County permitting and inspections operate together through the Permit Review Process12. A new residential unit or an addition of at least 500 square feet is subject to Dallas County's residential building-code materials when the site is outside a municipality's ETJ5. The published residential building-permit fee is $10013. Projects inside city limits go to that municipality14.
Who issues Dallas County building permits, and how do you reach them?
The Dallas County Department of Unincorporated Area Services is the first stop for unincorporated construction and development15. DUAS is at Records Building - 500 Elm Street, Suite 6100, Dallas, TX 75202; call (214) 653-6565 or email [email protected]15. Applications go through the county's online system with applicable forms, authorization, fees, plat, deed, scope of work, site plan and survey14. Planning questions go to Dallas County Planning and Development at (214) 653-76273.
Does Dallas County have zoning?
Dallas County has no authority to enact zoning, so unincorporated Dallas County has no county zoning districts2. County zoning sets no minimum dwelling size, minimum lot size, setbacks, lot coverage or building-height limit, and it does not prohibit RV, tiny-home or manufactured-home occupancy8. Dallas County still regulates floodplain development, subdivisions, septic systems and residential construction outside cities3. A new residence or an addition of at least 500 square feet outside a city's ETJ remains subject to the county residential-code process5.
How do septic permits work in Dallas County?
On-site sewage facility work requires a permit in unincorporated Dallas County6. Dallas County Health and Human Services handles septic questions for land outside city limits; call (214) 819-21154. Texas generally requires an approved plan and permit to construct, install, alter, extend or repair an OSSF7. A narrow exemption can apply to a single-family dwelling on at least 10 acres only when every state condition is met7. Only 4.1% of county soils lack severe conventional-drain-field limitations, so budget for site evaluation early16.
Can you live in an RV or tiny home on land in Dallas County?
Unincorporated Dallas County has no county zoning rule prohibiting RV or tiny-home occupancy and no zoning minimum for dwelling or lot size8. Physical placement is separate: DUAS requires a placement permit before putting a mobile home or recreational vehicle on unincorporated property9. A tiny home built as a new residence may enter the county residential-code and inspection process5. Development in a mapped floodplain also requires a Dallas County floodplain permit17. Describe the exact unit, foundation, utilities and intended occupancy to DUAS before buying.
What are the steps to build a home in Dallas County?
- Check flood status and obtain a permit for development in the unincorporated floodplain17.
- Apply through DUAS's online system with the required supporting materials14.
- Complete residential permitting and inspections12.
What should you check before buying land in Dallas County?
Confirm city-limit and ETJ status first145. Check floodplain status because covered development requires a county permit17. Budget for wastewater because only 4.1% of county soils lack severe conventional-drain-field limitations16. Confirm legal access: a county-road driveway requires a county permit, while state-highway access follows TxDOT's process1118. Dividing a tract into at least 2 parts may require plats before development or OSSF permits19. The effective property-tax rate is about 1.7%, with a median annual bill of about $4,6682021.
Watch-outs
- Dallas County permits apply only in unincorporated areas; city projects go to the municipality, and ETJ status can affect residential-code authority145.
- No county zoning restriction on RV occupancy does not eliminate the DUAS placement permit required before placing a recreational vehicle89.
- We could not confirm an owner-builder exemption; ask DUAS before relying on one10.
Sources
- Department of Unincorporated Area Services | Obtaining a Development Permit (2026 county census)
- Planning and Development | Zoning (2026 county census)
- Dallas County Planning and Development (dallascounty.org)
- Zoning and Other Related Regulations, quoted and re-checked
- Zoning and Other Related Regulations, quoted and re-checked
- Development Permit, quoted and re-checked
- Getting a Permit for an OSSF - Such as a Septic System (Texas statewide rule), quoted and re-checked
- Texas law on county zoning and building authority
- Dallas County Department of Unincorporated Area Services (DUAS) (dallascounty.org)
- (2026 county census)
- Applications and Permit Forms, quoted and re-checked
- Building Permit Application and Process, quoted and re-checked
- DUAS Fees Schedule, quoted and re-checked
- Development Permit, quoted and re-checked
- Dallas County Department of Unincorporated Area Services (DUAS) (dallascounty.org)
- Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
- Floodplain Administration, quoted and re-checked
- Section 4: Driveway Permits, Design, and Materials (Texas statewide rule), quoted and re-checked
- Subdivisions and Platting, quoted and re-checked
- Effective property tax rate: Bolthole Index county data
- Median property tax bill: Bolthole Index county data
Written September 28, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.